1. Field of the Invention
The present invention relates generally to a process for the concurrent production and hydrogenation of diisobutene. More particularly the invention relates to a process wherein isobutylene is dimerized and hydrogenated in a single distillation column reactor to produce desirable gasoline blending stocks, specifically the single step process produces 2,2,4-trimethyl pentane (isooctane). The resultant product which may be a mixture of isooctane, other C.sub.8 alkanes or alkenes is a superior blending stock for producing gasolines, including the CARB specifications.
2. Related Art
Conversion of olefins to gasoline and/or distillate products is disclosed in U.S. Pat. Nos. 3,960,978 and 4,021,502 wherein gaseous olefins in the range of ethylene to pentene either alone or in admixture with paraffins are converted into an olefinic gasoline blending stock by contacting the olefins with a catalyst bed made up of a ZSM-5 type zeolite. In U.S. Pat. No. 4,227,992, Garwood and Lee disclose operating conditions for the selective conversion of C.sub.3 + olefins mainly to aliphatic hydrocarbons. Also, U.S. Pat. Nos. 4,150,062 and 4,211,640 disclose a process for converting olefins to gasoline components. Chang, et al, in U.S. Pat. No. 5,608,133 disclose production of synthetic lubricants by oligomerization of C.sub.2 -C.sub.5 olefins and subsequent hydrogenation of the higher boiling olefins. A liquid phase process for the oligomerization of C.sub.4 and C.sub.5 isoolefins is disclosed in U.S. Pat. No. 5,003,124 wherein the reaction mixture is allowed to boil to remove the heat of reaction and a further dimerization is obtained in a reactive distillation column. U.S. Pat. No. 4,242,124 Smith discloses the reaction of isobutene with itself in a catalytic distillation column reactor to form diisobutene.
Brunelli, et al, in U.S. Pat. No. 5,510,555 disclose that the two isomers of diisobutene, 2,4,4-tri-methyl pentene and 2,4,4-tri-methyl-2-pentene when hydrogenated both yield 2,2,4 tri-methyl pentane which is the standard for octane measurement, i.e., RON=100 and MON=100.
Isooctane is not known to have been produced in a single step process of concurrent dimerization and hydrogenation heretofore.